Conventional lighting devices such as incandescent lamp, fluorescent lamp not only consume too much electricity by the lighting devices but also raise the surrounding temperature due to high heat dissipation that indirectly increase air condition load, and therefore cause global warming to harm the environmental protection.
For example, referring to FIG. 1, which shows a ceiling 1 of an office. The ceiling 1 is divided into a plurality of lattice 12 by a matrix of metal strip 11, some lattices 12 are installed with fluorescent lamp 13 for lighting. The fluorescent lamp 13 consumes too much electricity and dissipates too much heat, therefore it cause the disadvantages of the fluorescent lamp 13. However, LED consumes much less electricity and dissipates much less heat, so LED lighting devices become more popular and practical.
Facing the global warming problem, it is therefore an object of the present invention to save electricity consumption of the lighting devices and lower the heat dissipation in office.